This invention relates to a loading mechanism for a video tape recorder (VTR), etc., for withdrawing a tape from a cassette and making same travel along a predetermined path of travel before being returned to the cassette after completing its movement along the predetermined path.
One example of the loading mechanism for a cassette type VTR is shown in U.S. Ser. No. 7,974, now U.S. Pat. No. 4,258,399, (which corresponds to Japanese Patent Application Laid-Open No. 108606/79), in which rotation of an electric motor in the normal direction causes a belt through pulleys to rotate a worm and two worm gears. Connecting linkages secured at one end thereof by pins to the worm gears move in such a manner that the connecting pins move along guide grooves and are then drawn into the lower portions of the worm gears while being successively guided along arcuate grooves formed in the worm gears. The other end portion of each connecting linkage opposite the one end portion secured by the pin to one of the worm gears engages a tape withdrawing member serving concurrently as a tape guide, so that the tape withdrawing member also moves along such arcuate groove and reaches a catcher while withdrawing the tape from the cassette. The tape withdrawing member does not advance farther than the catcher. At this time, the connecting pin connecting one link member of one of the connecting linkages secured by the pin to the next link member has moved to the terminating end portion of the arcuate groove of each worm gear, so that each worm gear stops rotating any further.
Some disadvantages are associated with the mechanism of the aforesaid construction. In this mechanism, it is difficult to set a large angle of rotation for each worm gear to rotate after the tape withdrawing member, serving concurrently as a tape guide, has moved to a predetermined position. Thus, difficulties would be experienced in further rotating the worm gears and manipulating the connecting linkages by the rotation of the worm gears. If the worm gears are forcibly rotated, the problem would arise that the reliability of the mechanism might be lowered in performance. By additionally using a motive force generating element, it would be possible to obtain a mechanism of high reliability in performance. However, this would entail a rise in cost which is not desirable.